The Effects Of Adiponectin On Enzymatical Activity And Gene Expression Of Glucokinase And Phosphoenolpyruvate Carboxykinase In Cultured Rat's Liver Cells

Objective: To investigate the effections of adiponectin on enzymatical activity and gene expression of glucoskinase(GK) and phosphoenolpyruvate carboxykinase(PEPCK) in cultured rat liver cells,and to explore the mechanism of how adiponectin effects liver's insulin resistance (IR). Methods: The BRL cell was used as cell model. Rat'liver cells were incubated with adiponectin of three different concentrations (10μg /ml,30μg /ml and 50μg /ml).Controled cells were incubated without adiponectin. Enzymatical activity of GK was tested with a standard G6P-coupled assay,and enzymatical activity of PEPCK was tested with a standard LDH-coupled assay.RT-PCR was used to determine GK and PEPCK gene expression (corrected by β-actin). Results: (1) Comparing with the control group, enzymatical activity of PEPCK significantly decreased even in the lowest concentration of adiponectin, the more the adiponectin concentration increased,the more the enzymatical activity of PEPCK decreased(P<0.05), the result of RT-PCR also showd that the mRNA expression of PEPCK significantly decreased after being treated with adiponectin of different concentrations. (2)Comparing with the control group,enzymatical activity of GK had no significantly decreased after being treated with adiponectin of different concentrations. The result of RT-PCR show that adiponectin has no effect on GK mRNA expression either. Concludes: Adiponectin can't affect ezymatical activity and mRNA expression of GK significantly. However adiponectin decreases enzymatical activity and mRNA expression of PEPCK significantly.Through this way,adiponectin decreases liver glucose production and improve insulin resistance.